Technology for making a condensed mat of glass fiber strands is well known in the art and the system is described fairly well in several patents to Modigliani, U.S. Pat. Nos. 2,546,230; 2,609,320 and 2,964,439. Each of the patents describes a melting furnace feeding molten glass to spinning orifices which discharge fine glass fibers, which in turn are wrapped circumferentially around a spinning drum. During the deposition of the fibers on the rotating drum, a thermosetting resin is applied to the surface to hold the fibers at their overlapping junctions between layers.
Ordinarily the furnace and spinning orifices move longitudinally along the rotating drum during the assembly process. The translation of the furnace with respect to the drum is relatively slow and the drum is rotating relatively fast to provide a build-up of a plurality of layers of the glass fibers.
After a suitable thickness of fibers has been created, the condensed mat is severed from the drum by a cut across the mat parallel with the axis of the drum. Thereafter, the condensed mat is deposited on a conveyor belt which moves longitudinally at a very slow pace. The severed condensed mat is generally rectangular in shape and the fibers are continuous for the most part and extend completely across the width of the mat in a direction generally perpendicular to the direction of movement of the conveyor belt.
At the exit end of the conveyor belt, a retarding roller presses the condensed mat against the conveyor belt which is supported by an oppositely rotating support roller. The leading end of the condensed mat beyond the retarding roller is stretched or expanded longitudinally up to 500 or 600 times the original length of the condensed mat. The expanding is a continuing process with the leading end being pulled longitudinally while the confining-retarding roller minimizes the forward movement of the remaining condensed mat.
As the mat is expanded longitudinally, it also fluffs vertically to a consistency somewhat like cotton candy and the transversely extending fibers are pulled longitudinally tending to rotate and reorient the fibers such that they assume a 45.degree. or greater angle with respect to the longitudinal direction as the mat is stretched and necks down to a smaller width.
After the majority of the expanding takes place, the fluffed, expanded mat is rolled to confine it to a thinner mat and it is heated by radiant heaters to set the thermosetting resin incorporated during the deposition of the fibers on the drum. Thereafter, the stretched glass fiber mat is wound on a drum where it may be transported to other locations for use in various embodiments such as heat, thermal and sound insulation and filters as an example.
A patent to Simkins et al., U.S. Pat. No. 2,644,780, defines a similar process which includes stacking a plurality of mats to have a thicker resulting mat for use.
A patent to Copenhefer, U.S. Pat. No. 2,984,286, discloses a glass filament feeding technique which purports to improve the quality of the mat deposited on the drum.
A patent to Schlarb, U.S. Pat. No. 3,072,513, discloses another technique for treating the fibrous mat during its expansion to improve its qualities.
A patent to Beckner, U.S. Pat. No. 3,092,533, discloses an apparatus and process for controlling the thickness of the expanded mat.
What none of these patents disclose is a way of making a continuous series of glass fiber panels from the expanded mat with the mat having a substantial pattern and transverse relief as molded.